For evaluation of drug functions etc., attempts have been made to differentiate pluripotent cells such as embryonic stem cells (ES cells) or induced pluripotent stem cells (iPS cells) into hepatocyte-like cells (also referred to as “liver cells” hereinafter). A known method for inducing differentiation of the pluripotent cells into the liver cells is transferring a gene involved in liver cell differentiation into the pluripotent cells. Non-Patent Document 1 discloses a method for inducing differentiation of pluripotent cells forming cell clusters into liver cells.
However, the gene transfer has a risk of cancerous transformation of the cells to which the gene has been transferred, for example. Also, the method disclosed in Non-Patent Document 1 has problems in that: most of the cells die at an early stage of differentiation; and it is difficult to produce uniform cell clusters suitable for the liver cell induction.